Those that purchase the game second-hand will find themselves unable to participate in the game's Catwoman content, which is tied to a code inlcuded with all new copies of the game.
If you do happen to buy the game used, you'll be able to purchase a new online pass — and subsequently access the Catwoman content — for £7.99 from the PlayStation Store.
Warner Bros explained that the Catwoman content "is not required to complete the game". Obviously if you're planning on purchasing the game new, you won't need to worry about missing out on any content. Well, aside from all those pre-order exclusive character skins anyway.